One or more aspects of embodiments of the present disclosure herein relates to an organic electroluminescent device.
Recently, developments of display devices and lighting devices using an organic electroluminescent (EL) device (which is a self-luminescent device) have been actively conducted. However, organic EL devices having improved performance are still needed for the application in the display device and the lighting device.
An organic EL device has, for example, a laminated structure of an anode, a hole injection layer, a hole transport layer, an emission layer, an electron transport layer, an electron injection layer, and a cathode. In such organic EL device, holes and electrons respectively injected from an anode and a cathode recombine in an emission layer to generate excitons, and the emission of light may be attained via the transition of the formed excitons to a ground state.
Techniques of improving a hole transport layer of an organic EL device have been described in the related art. For example, a hole transport material improving the emission property of an organic EL device has been disclosed. A technique of improving the emission property of an organic EL device by adding an electron accepting material to a hole transport layer, etc. has also been disclosed. In addition, technique of improving the emission property of an organic EL device by forming a hole transport layer having a laminated structure of multiple layers have been disclosed.